Warning: ORA-16826: apply service state is inconsistent with the DelayMins property

Error: Warning: ORA-16826: apply service state is inconsistent with the DelayMins property

Details: Gotten this warning after switching over from primary to standby. All redo logs were applied and no errors showed up in alert log, but DataGuard shown the warning in standby

Cause:
Solution:
When I executed:

SELECT DEST_NAME,DATABASE_MODE,RECOVERY_MODE,PROTECTION_MODE,STATUS FROM V$ARCHIVE_DEST_STATUS
WHERE DATABASE_MODE='MOUNTED-STANDBY';

I'd get:

--------------------------------------------------------------------------
DEST_NAME           DATABASE_MODE   RECOVERY_MODE           PROTECTION_MODE      STATUS
--------------- ----------------------- -------------------- --------------
LOG_ARCHIVE_DEST_3  MOUNTED-STANDBY    MANAGED               MAXIMUM AVAILABILITY VALID

So RECOVERY_MODE came up as "MANAGED", meanwhile it should have been "MANAGED REAL TIME APPLY". Restarting MRP, as it was suggested by every source I could find, did not help and the next solution was to do that with NODELAY keyword:

ALTER DATABASE RECOVER MANAGED STANDBY DATABASE CANCEL;

ALTER DATABASE RECOVER MANAGED STANDBY DATABASE NODELAY;

That did not help either. I waited until next logfile switch but the warning was still there. Finally I decided to remove the standby database and then re-add and re-enable it but gotten an error on the attempt to remove it:

DGMGRL> remove database 'Stby';

Error: ORA-16627: operation disallowed since no standby databases would remain to support protection mode So my last resort was to disable and re-enable Data Broker configuration:

DGMGRL>disable configuration;

DGMDRL>enable configuration;

Then

DGMGRL>show configuration;

finally returned SUCCESS.